A gas-liquid chromatographic method for the quantitative determination of quinidine in blood

A gas-liquid chromatographic method, using chloroquine as internal standard, for quinidine evaluation in serum is described. Prior to acidic delipidation, chloroquine is added to the serum sample and an alkaline extraction is used. Direct gas-liquid chromatographic analysis of unaltered forms using a nitrogen detector is performed. The sensitivity limit of this method is 0.5 microng/ml, i.e. sufficient for therapeutic quinidine blood level determinatin (1 to 5 microng/ml).